The concept of a device to hold a motorcycle throttle still is well-known, and more than 30 thirty years old. Many have been patented, and many are currently on the market. The invention distinguishes itself by the combination of its simplicity, safety, reliability, ease of use, easy setup, range of application, simple appearance, and its taking up no room on the handlebars. An evaluation of the prior art resulted in the selection of the above references, which appear to be representative of the basic sorts of solutions so far offered.
Here follows a summary of the basic methods so far employed.
Some employ a threaded member to interfere to varying degrees with the portion of the throttle sleeve that is inside the control housing given on the motorcycle. This method depends greatly for its practicality on a preexisting threaded hole in the control pod. If this hole is not present, installation is much more involved. As well, engineering smooth, precise, repeatable action that guarantees overrideability in an emergency has proven challenging with this method.
Others append mechanical teeth to the fixed portion of the handlebar and to the portion that rotates with the twist-grip, and make provision for selectively engaging them together, locking the twist-grip in position. One inboard side approach presents an uneasy tension between complexity, ugliness and high parts count on one hand, and having to make a profusion of expensive application-specific parts on the other. As well, the approach of interlocking gear teeth requires overrideability to be specifically engineered into the system to a degree not present in the other methods, since gear teeth tend to interlock positively.
Others provide a selective frictional engagement between the outboard moving end of the twist-grip and the fixed handlebar. Selective outboard frictional engagement is also employed by the invention. The application-specific features of the outboard end of the handlebars are typically confined within the perimeter of the end of the grip, so special parts to engage them can be compact, inexpensive, and well-hidden. As well, no space on the handlebar is consumed, a major advantage to the user, as many accessories are best mounted on the handlebar. The biggest challenge of this method are that twist-grips have different amounts of axial play, and different biases as to where they sit within that play, and different ways that grips respond to pressure, so a good mechanism must be able to absorb that play. Conventional solutions have not met this challenge sufficiently. The next challenge of this method is to fully utilize the potential for broad applicability of a twist-grip locking device. Conventional solutions have absolutely not met this challenge, with some confined to hollow bars and others to external mounting on bars with modest-size internal threads.
Others provide a selective frictional engagement by external clamping action between some inboard portion of the twist-grip assembly, and some portion of the fixed handlebar or control pod. This inboard side approach, as with another mentioned above, presents an uneasy tension between complexity, ugliness and high parts count on one hand, and having to make a profusion of expensive application-specific parts on the other. These units also inevitably take up some axial room on the grip, the throttle sleeve, or the handlebar.